Terrorist and extremist content is being removed from the internet at a rate of nearly 300 pieces every day, new figures have revealed.
A national unit established to target the material has seen its workload surge dramatically following the rise of Islamic State, which has assembled a vast online propaganda machine.
Statistics released by Scotland Yard as police launched a new drive, calling on the public to flag up terror-related material they encounter on the web, showed that:
:: The Counter Terrorism Internet Referral Unit (CTIRU) has prompted the removal of more than 160,000 pieces of extremist or terrorist material since it began work in 2010.
:: Removals have risen from less than 2,000 in 2012 to 55,556 in 2015 - or around 1,000 a week - meaning more than a third of the total volume taken down to date was wiped out in a single year.
:: In the first three months of this year 26,479 pieces were removed - equivalent to 291 a day. If this rate continues, the total for 2016 would exceed 100,000.
:: The number of reports about material from concerned members of the public has also increased, reaching nearly 3,000 last year.
The dedicated unit instigates the removal of content such as terrorist propaganda videos, pictures of beheadings, bomb-making instructions and speeches calling for racial or religious violence.
Once an item has been identified, the CTIRU sends the internet service provider an advisory note, seeking its removal.
The capacity of IS - also known as Daesh - to exploit the internet to broadcast its activities and message is a major challenge for security services around the world.
The Met said: "There has been a rise in the amount of extremist and terrorist material online being removed, which is attributed to a range of factors including the proliferation of Daesh propaganda, communities becoming more willing to report material and counter terrorism policing's proactive approach in tackling it."
In response to the escalating threat the number of staff and officers working within the CTIRU has been increased this year.
Today police forces around the country are appealing for internet users to report harmful extremist and terrorist content when they see it online, while the unit is embarking on a 36-hour operation to secure the removal of material as quickly as possible.
People can flag material they suspect is extremist or terrorist by clicking on a red "stop" button on police and partner websites which takes them to a short, anonymous form.
Deputy Assistant Commissioner Helen Ball, Senior National Coordinator for Counter Terrorism Policing, said: "Tackling extremist material is important to protect the public and prevent offences that incite or promote terrorism and extremism.
"The internet and social media provide many opportunities for those with extreme views to target young or vulnerable people and their methods are constantly evolving, from using new phone apps to hijacking popular hashtags in order to reach wide audiences."
She added: "Police depend on information from the public in our efforts to help keep us all safe and we are asking anyone who has concerns about online content to report it by clicking the red STOP Terrorists and Extremists Online button."
Minister for Internet Safety and Security Baroness Shields said: "I applaud the world-leading work of the police Counter Terrorism Internet Referral Unit and would urge the public to report terrorist and harmful extremist content when they see it."